Gas in Marcellus Water Wells Is Explosion Risk, Study Says

By Mike Lee -
May 9, 2011

Natural gas is leaking into well water
in New York and Pennsylvania from nearby drilling sites,
according to a study by Duke University.

Water wells within 1 kilometer (0.6 miles) of gas drilling
had 17 times more methane than more distant wells, according to
the findings. The results are the first peer-reviewed study to
show a link between well water and drilling in the Marcellus
Shale, a band of rock in the eastern U.S., said Robert Jackson,
a Duke professor who is one of the authors of the study.

The Duke researchers didn’t test water from municipal
supplies, rivers or lakes. They found no evidence of the
chemicals used as part of the rock-fracturing process common in
natural-gas drilling.

Gas found in the water probably escaped through faulty well
casings on Marcellus gas wells, Jackson said. Some gas may also
seep naturally from shallower formations closer to the aquifers
feeding the wells, Jackson said. The levels of gas were high
enough to cause a risk of explosion, according to the study,
published today in the Proceedings of the National Academy of
Sciences.

The Duke research bolsters the argument that most drilling-
related pollution comes from poor well construction, not from
fracturing, Scott Anderson, a senior policy adviser for the New
York-based Environmental Defense Fund, said in an interview.

The results come amid a growing debate about the
environmental effects of gas drilling in the Marcellus Shale and
similar rock formations where rocks must be fractured to make
the gas flow in commercial quantities.

The Environmental Protection Agency is studying the effects
of gas fracturing on water supplies. In December, the agency
ordered Range Resources Inc. to clean up around two wells after
gas turned up in residential wells near Fort Worth, Texas.

Pennsylvania has a history of naturally occurring water-
well contamination, Aubrey McClendon, chief executive officer of
Chesapeake Energy Corp. (CHK), said in an April 8 speech in Dallas.
Chesapeake is the most active driller in the U.S. and is
searching for gas on 1.6 million acres in the Marcellus Shale
region.

“You can go back 100 years and people talk about gas in
their water wells,” he said. “It’s not from fracking.”

‘Engineering Solution’

McClendon said Marcellus drilling may have contributed
“inconveniences,” and said “every one of those problems has
an engineering solution to it.”

The researchers tested 68 sites across five counties in
Northeastern Pennsylvania and New York. Gases such as methane,
ethane and propane were found in the water at 85 percent of the
sites tested. The concentrations were higher the closer the
samples were taken to gas drilling sites.

Researchers found that some of the gas sampled from the
water wells originated from the same deep rock tapped by gas
drillers, as opposed to the gas that naturally seeps from
shallower formations. Those samples showed “specifically
matching natural gas geochemistry from local gas wells,” the
researchers said in their paper.

Data Lacking

“This study lacks key data that would be needed to
validate its conclusions,” Daniel Whitten, a spokesman for
America’s Natural Gas Alliance, a Washington-based trade group,
said in an e-mail. “The existence of methane in the environment
is often due to naturally occurring geological phenomena that
has no relation to natural gas development.”

On April 19, Pennsylvania regulators asked gas companies to
stop disposing of drilling wastewater at sewage treatment plants
after drilling-related byproducts turned up in local rivers.
Pennsylvania enacted tougher regulations for gas wells in 2010
and began requiring drillers to test water within 1,000 feet of
new drilling sites.

An April 12 study by Cornell University calculated that gas
extraction from shale formations contributed more to global
warming, over its life cycle, than oil or coal.

Aquifer Samples

Much of the water studied by the Duke researchers
originated in the Lock Haven aquifer, an underground system that
supplies wells in northeastern Pennsylvania. The researchers
didn’t cite any corresponding samples from the Lock Haven
aquifer that weren’t affected by drilling, said John Conrad, a
consulting geologist who has done tests for the gas industry.

“I’m not sure you can take 68 wells over a very broad
geographic area and make any statistical conclusion,” he said.
“Methane types and methane concentrations can vary radically
over very short distances.”

Jackson said the Duke researchers plan to collect more
samples in the Lock Haven aquifer.

“If the companies would be willing to help us sample some
non-active wells and have homeowner contacts in that area, we’d
love to get them,” he said in an e-mail.

A database should be created that would include all the
research on the affects of natural-gas drilling on water
supplies, Jackson said. He’d also like to see research showing
the effect of methane on human health.

“It needs a lot of follow-up, by not just us but by many
other groups, too,” he said.

To contact the reporter on this story:
Mike Lee in Dallas at
Mlee326@blooomberg.net.